1. Field of the Invention
The invention relates to the field of the lighting and/or signaling systems for motor vehicles. It relates more particularly to a cooling member for such a system.
A particularly advantageous but nonlimiting application of it is in the field of vehicle headlights.
2. Description of the Related Art
Motor vehicle headlights usually consist of a housing which is closed by a transparent wall through which one or more light beams emerge. This housing houses at least one optical module, mainly comprising a light source and an optical system suitable for modifying at least one parameter of the light generated by the light source for the emission of the light beam by the optical module.
The trend in the technology tends to favor the use of light sources made up of at least one LED (light-emitting diode), because of their low energy consumption, their small footprint and the quality of the lighting obtained.
However, the LEDs have the drawback that, in use, they produce heat which is damaging to their operation. In effect, the hotter an LED becomes, the more its light flux decreases.
When the optical module is designed to generate a beam requiring a strong light intensity, such as for low beams, high beams or fog lamps. The number of LEDs and/or the power necessary for their operation is high. As an indication, such a high operating power is likely to lie between 5 W and 60 W.
To ensure an effective cooling inside the housing above an operating power of 10 Watts (10 W), it is known practice from the document WO2005116520 to induce a forced passage of a flow of air along fins, according to the orientation of the general direction of emergence of the light from the optical module. The use of such a forced flow of air presents the drawback of having to implement specific means to provoke the flow of air and of increasing the bulk inside the headlight. The cost and the complexity of the headlight are also high.
It has also been proposed to arrange a heat dissipater in the form of fins or of a molded plate in contact with the LED. The documents FR2840151, which is equivalent to U.S. Publication 2004/0029436 which issued as U.S. Pat. No. 6,821,143, and FR2853200, which is equivalent to U.S. Publication 2004/00190294 which issued as U.S. Pat. No. 7,210,833, present this type of plate. These solutions have the drawback of offering a limited efficiency for discharging the calories.
Thus, despite the existing solutions, there is still a need to propose the solution for more effectively cooling a lighting and/or signaling system while retaining a limited bulk and complexity.